- Four-minute test clip now available on BBC iPlayer

- It's streaming in Ultra HD and HDR

- Uses HLG, a new HDR format that's back-compatible

The BBC is streaming a clip in Ultra HD and HDR on BBC iPlayer, allowing you to watch a small section of Planet Earth II in the highest quality ever.

The four-minute clip is a test. It'll only be available on a "small selection of the latest TVs", enabling the BBC to examine the impact of broadcasting in this higher quality, something that's so far been the preserve of streaming services like Netflix and Amazon, or via Ultra HD Blu-ray discs.

The BBC is considering this broadcast a "public Ultra HD and HLG test". Hybrid Log-Gamma, which is a form of HDR, was developed by BBC R&D and Japanese broadcaster NHK, and it has seen some testing previously, but this is the first time that it will be publicly available to watch.

"The experiment is an early but important step toward streaming high-quality Ultra HD programmes on BBC iPlayer in the future," explained the BBC. "Central to the trial is the inclusion of HLG, which the BBC sees as an integral part of future Ultra HD programming. Where Ultra HD improves image quality ... HLG takes this one step further by providing better quality pixels."

While Ultra HD, or 4K, is a familiar technology, HLG might not be; HLG has been designed as an alternative to existing high dynamic range systems, aiming to increase the contrast and colours shown on TV. In the case of the Planet Earth II trial, HLG means that "a shade of red never before seen on a TV" can be shown.

The advantage that HLG offers is that it's not dependent on having the latest equipment at all points. It's back compatible, meaning that it works with existing hardware, reducing the costs and demands on the creator and the viewer. The four-minute-long Planet Earth II clip will be available in Ultra HD and HLG on BBC iPlayer until early 2017. The BBC has not yet confirmed which TVs will be supported.

We suspect the list will include LG OLED TVs, which were used in a trial earlier in the year. We'll update if we hear more.

Planet Earth II will blow your socks off in HD. We can't wait to see the impact of UHD and HLG.